As automakers spend billions to rack up autonomous miles and map city streets, Toyota Motor Corp. and BMW AG are also betting on a startup with a more modest approach.

The corporate venture arms of the two carmakers led a $11.5 million seed investment round for May Mobility, a micro-transit company that deploys self-driving electric shuttles short distances. The Ann Arbor, Michigan-based company plans to use the seed money to expand into Texas and Florida.

By running one-kilometer routes on repeat, May Mobility's shuttles gather critical information in the path toward full autonomy.

"Something we can give them access to is that early rider-experience data that we're collecting," said Chief Executive Officer Ed Olson. "We can make sure we've got the acceptance factors for autonomous vehicles right."

With truly self-driving vehicles still years away, more startups are trying to take smaller bites out of the engineering challenges of going driverless -- and hopefully make money along the way. May Mobility's main customers are property developers who want to transport people from parking lots quicker and cheaper, plus municipal planners looking to replace underutilized bus routes, Olson said.

That real-life experience has strategic value for automakers' own driverless research.

May Mobility, which was founded last year and charges a monthly fee for its shuttle service, plans to use the seed money to expand in Texas and Florida because those states that don't require a safety driver, said Olson, who's also a professor of computer science and engineering at the University of Michigan. The company will hire technicians to service and clean the shuttles, as well as supervise the routes.